Re: [PATCH net-next] net:drivers/net: Miscellaneous conversions to ETH_ALEN

[Julia Lawall <julia.lawall@lip6.fr>]

On Wed, 2 Oct 2013, Joe Perches wrote:

> On Wed, 2013-10-02 at 10:44 -0700, Luis R. Rodriguez wrote:
> > On Tue, Oct 1, 2013 at 11:40 PM, Joe Perches <joe@perches.com> wrote:
> > > Please include netdev.  (cc'd)
> > >
> > >> Joe Perches <joe@perches.com> writes:
> > >>
> > >> > Convert the memset/memcpy uses of 6 to ETH_ALEN
> > >> > where appropriate.
> > >
> > >> > Signed-off-by: Joe Perches <joe@perches.com>
> > 
> > I think these sorts of patches are good -- but once applied it'd be
> > good if we can get the SmPL grammar expressed for it and then have
> > developers / maintainers regularly doing:
> > 
> > make coccicheck MODE=patch M=path > path-cocci.patch
> > 
> > Unfortunately right now MODE=patch takes about 3 1/2 minutes for
> > ath9k, MODE=org takes ~10 minutes for ath9k (17 minutes for all of
> > ath/), and MODE=context takes ~8 minutes on ath9k -- I do believe its
> > a bit unreasonable to expect patch submitters to use this, but
> > certainly great practice. Some of the time differences on the reports
> > can be explained by the fact that some SmPL will only be used for some
> > modes.
> > 
> > Even though it takes a while right now it'd be great practice to use
> > coccicheck to prevent these type of changes from going in again,
> > things that checkpatch.pl won't be able to catch.
> 
> As far as I can tell, it's basically not possible for cocci to
> do this conversion.

I tried looking for memcpys and memsets that do use ETH_ALEN and then 
seeing what non-local functions the affected values flow to.  I then 
marked all of the calls to memcpy and memset that use 6 where an affected 
value flows to one of the functions identified in the first pass.  I get 
40 unique results on Linux 3.10.

The semantic patch is below.  It needs to be cleaned up to not return 
duplicate results.  It needs to be run with the argument --no-show-diff, 
and the result is printed in emacs org mode.

julia

virtual after_start

@initialize:ocaml@

let neighbors = ref []
let local_functions = ref []
let reset = ref false

let do_reset _ =
  if not !reset
  then
    begin
      reset := true;
      let it = new iteration() in
      it#add_virtual_rule After_start;
      it#register()
    end

@script:ocaml depends on !after_start@
@@

local_functions := []

@locl@
identifier f;
@@

f(...) { ... }

@script:ocaml@
f << locl.f;
@@

local_functions := f :: !local_functions

@r depends on !after_start@
identifier f;
expression e,e1,e2;
@@

(
memcpy(e,e1,ETH_ALEN)
|
memcpy(e1,e,ETH_ALEN)
|
memset(e,e1,ETH_ALEN)
)
... when any
    when != e = e2
f(...,e,...)

@script:ocaml@
f << r.f;
@@

if not (List.mem f !local_functions) && not (List.mem f !neighbors)
then begin neighbors := f :: !neighbors; do_reset() end

@r1 depends on !after_start@
identifier f;
expression e,e1,e2;
@@

f(...,e,...)
... when any
    when != e = e2
(
memcpy(e,e1,6)
|
memcpy(e1,e,6)
|
memset(e,e1,6)
)

@script:ocaml@
f << r1.f;
@@

if not (List.mem f !local_functions) && not (List.mem f !neighbors)
then begin neighbors := f :: !neighbors; do_reset() end

// --------------------------------------------------------------------------

@s depends on after_start@
identifier f;
expression e,e1,e2;
position p;
@@

(
memcpy@p(e,e1,6)
|
memcpy@p(e1,e,6)
|
memset@p(e,e1,6)
)
... when any
    when != e = e2
f(...,e,...)

@script:ocaml@
f << s.f;
p << s.p;
@@

if List.mem f !neighbors
then Coccilib.print_main "" p

@s1 depends on after_start@
identifier f;
expression e,e1,e2;
position p;
@@

f(...,e,...)
... when any
    when != e = e2
(
memcpy@p(e,e1,6)
|
memcpy@p(e1,e,6)
|
memset@p(e,e1,6)
)

@script:ocaml@
f << s1.f;
p << s1.p;
@@

if List.mem f !neighbors
then Coccilib.print_main "" p